Photo-mechanical method of producing technical drawings and the like



Feb. 21, 1961 L. G. FRANKAU ETAL 2,972,533 PHOTO-MECHANICAL METHOD OFPRODUCING TECHNICAL DRAWINGS AND THE LIKE Filed Dec. 7, '1955 2Sheets-Sheet 1 LAYS L06.

Inventors Louis 6. Frankau, Arthur P Pisacane, b m

The Attor'neg.

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Feb. 21, 1961 Filed D90. 7, 1955 L. G. FRANKAU ET'AL 2,972,533PHOTO-MECHANICAL METHOD OF PRODUCING TECHNICAL DRAWINGS AND THE LIKE 2Sheets-Sheet 2 Fig.3.

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I I Louis GfFra'nkau,

Arthur F. Pisacane,

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States Paten PHOTO-MECHANICAL METHOD or PRODUCING TECHNICAL DRAWINGS ANDTHEVLIKE' Louis G. Frankau, Upper Darby, and Arthur F. Pisacane,Landsdowne, Pan, assignors to Genera! Electric Company, a corporation-ofNew York Filed Dec. 7,-195'5, Ser. No. 551,644

4 Claims. (Cl. 96-.'43)

This invention relates to a photo-mechanicalmethodof producing technicaldrawings and the like.

Frequently, the drawings which are used in certain technical fieldscontain a large number of standard symbols and components which appearrepetitively. in different drawings, though in varying locations andcombinations.

One approach toward reducing the time required forduplicating thesevarious standard symbols on each different drawing has involvedpreparing a group of appliqucs, or overlays, which individually depict.various symbols,

and then attaching these overlays in their proper locations Accordingly,an object of our invention is toprovide,

for the purpose of producing technical drawings and the like, a new andimproved overlay method in which the various overlays used in practicingthe method can be applied accurately and rapidly by a relativelyfunskilled person. i

Another important factor in determining the success of such a method iswhether the final drawings, or prints,

conform to the high standard of quality which is gen erally required. Inthis connection, it has been fou'nd that where the format sheet, as wellas theattached overlays, contains printed matter, -it is difficult toohtain fa sharp and dense reproduction of all of the printed matter.

For example, in prior overlay methods where conventional contactreproduction procedures were used, those image lines on the final printwhich were derived from the overlays sometimes appeared blurred and'consider-. ably thinner than corresponding image lines derived from theformat sheet.

Accordingly, another object of our invention is to assure that thoseimage lines on the final print which are derived from the overlays aredense and sharp andof substantially the same thickness as correspondinglines derived from the format sheet.

Another object is to provide an overlay method which readily lendsitself to the use of reusable components which can be easily identifiedby markings which do not appear on the final print. i

In carrying out our invention in one form, the fol low-' ing componentsare first provided: (1) at least one transparent format sheet containingcertain basic illustrative material, (2) a plurality of differenttransparent overlays each containing certain additional illustrativematerial, such as device symbols, (3) a location index sheetco utainingcoded indicia coordinated with the format sheet, and (4) a codedinstruction form assigning selected overlays to certain locations on thelocationindeit sheet.

This instruction form is prepared by an engineer or tech-- nician who isfamiliar with the subject matter of the proposed drawing, butthe. steps.which.,follow.can be carried, out -by aperson having no such knowledge.Thesesteps are as follows: the transparent format sheet is firstsuperimposed on the location index sheet, which is visibletherethrough.'- Then, using the location index sheet as a guide,selected overlays are attached to the format-.isheet in, locationsassigned by the coded instruction form. When all, of the requiredoverlays are attached to theformatsheetin their proper locations, theformat sheet withthe overlays attached thereto is, removed from thelocation index sheet and used as apositivefrom which prints are. made byany suitable conventional methodlof reproduction.

in the preferred form of our invention, both the, format sheet and theoverlays comprise sheets of positive film having their. printedmatterformed'in a photographicallydeveloped coating on. one side of the film.The printed matter on. the format sheet is off such a nature that it ispositively readable from the coating side of the format sheet, but theprinted matter on each of the overlays is of. such. a naturethat it isreversely readablefrom the coating sideof the overlay. The overlays areattachedv to the format sheet with their respective coatings in contactwith the. coating side of the format sheet, thus producinga compositepositive film transparency which is positively readable from the coatingside of format sheet.

Used thereafter in a conventional contact-type photo-me chanicalreproduction process, this compositelends itself in a veryeffective'manner to the production of prints having sharp, 'dense linesof consistent thickness. This is the case because the images onboth theoverlays and the format'are in substantially the same plane and areerrposed through onlya single thickness'of filmduringthe I reproductionprocess.

For atbetter understanding Of'our invention,' -reference may bel hadtothe following specificationtaken in connection with the accompanyingdrawing in'which Figs. let-through 1d illustrate certainbasic componentswhich are used in practicing the method of our invention; Figs. 2through 5 illustrate the various steps which constitute the method andwhich utilize the components of Figs. 11; through It! and Fig. 6 is anenlarged cross-sectional View taken 'along the line. 6--6 of Fig.5 andshowing certain of the-components in assembled relationship.

Referring now to Figs.- la through I'd, the basic components showntherein for practicing the'fmethod of the present "invention comprise alocation indexsheet 10, a format sheet'll, a'plur'ality of overlays 12,and acoded instruction form 13.

The format sheet ll is a transparent sheet of positive film havingprinted thereon certain basic illustrative matter which it is desiredshould appear in the final drawing. Thisbasic illustrative matter is ofsuch a nature that it appears unchanged in all of the various drawingswhich it'might be desired to make from these components.

The overlays 12, which are shown in an enlarged form in Fig. 1c, arealso transparent sheets of positive film and have printed thereoncertain standard symbols representing components which it is desired todepict in the parent sheet of film. Printed ,on this index sheet 10 iscertain indicia which is subsequently utilized, aswill soon appear, toprovide a guide for locating the over lays lz'on'the format 11. Thisindicia ma take any i suitable form, .butfor illustrative purposes, wehave shown the indicia as comprising a series of blocks, each identifiedby one of a series of letters.

The engineer or technician who is seeking the drawing first determinesthat certain devices, which are individually depicted by the variousoverlays, should be-used at certain locations on the drawing. He thenrefers to the location index sheet and assigns the selected overlays toparticular locations selected on the location index sheet. Thisselection process is recorded on the coded instruction form in anysuitable predetermined manner, as forexample, by filling in adjacentspaces on the form with the identifying letter of a particular locationblock and the number of the overlay selected therefor, as shown in Fig.1d.

This coded information form is then referred-tea clerk, who need have noknowledge of the subject matter of the proposed drawing. In accordancewith our invention, the clerk first tapes the location index sheet 10 toa suitable working surface, such as the top of a light table 15, asshown in Fig. 2. The format sheet 11 is then superimposed upon thelocation index sheet and taped in place in a predetermined positionthereon, as is shown in Fig. 3. Correct positioning of the format sheetis achieved preferably .by bringing into registry certain preselectedmarks, such as the frames on the two sheets;

Then, the clerk selects the various overlays designated on the codedinstruction form and attachs these overlays, as by transparent .tape, tothe format sheet in the locations specified by the instruction form. Thelocation index sheet is, of course, .visible through the translucentformat sheet 11 and accordingly serves as a guide for achieving preciselocation of the various overlays on the format sheet. Fig. 4 shows theformat sheet after some of the overlayshave been attached thereto, Whenall'of the required overlays are attached to'thef format sheets in theirproper locations, the format sheet with its overlays is thenremoved fromthe location index sheet, as is shown in Fig, 5. This composite, i.e.,the positive format sheet having the positive overlays attached thereto,subsequently serves as a positive from which prints are produced by anysuitable conventional contact-type photo-mechanical reproduction method.

Preferably, a sheet of translucent autopositive material, such asautopositive paper, is used for each of these final prints. Thisautopositive paper,rwhich is of a conventional form, has a lightsensitive emulsion coating one of its surfaces. In accordance withconventional reproduction procedures, this emulsion on the auto.positive paper is placed in contact with the positive film compositeand-is then suitably exposed. Thereafter, the: sheet of autopositivepaper is removed from the fi'm, and is suitably developed to produce onits emulsion side an image of theprinted matter on the film. V

The use of positive film overlays hasusually been avoided because theprints obtained by using conventional contact-type reproductionprocedures, such as described above, were not of the required highquality. For ex-' ample, we have found with prior overlay methods thatthose image lines on the final print which were derived from theoverlays sometimes appeared blurred and considerably thinner thancorresponding image lines derived from the format sheet itself.

To overcome this problem and thereby produce prints having sharp, denselines of consistent thickness, a novel relationship of the overlays andthe'format sheet has been devised. More particularly, the overlays,which are formed of positive film having a photographicallydevelopedcoating located on one side, have their printed matter formed in thecoating in such-a manner that it is reversely readable when viewed fromthe coating side. On the other hand, the format sheet, which is also ofpositive film having a photographically-developed coating located on oneside, has its printed matter formed, in the coating in such a mannerthat it is positively readable from its coating side. In producing thecomposite 4 film assembly, the overlays are attached to the format sheetwith the coating of each of the overlays in contact with the coatingside of the format sheet. This relationship is illustrated in Fig. 6,which is a cross-sectional view of a portion of the composite takenalong the line 66 of Fig. 5. The overlay 12 of Fig. 6 is shown with itsphotographically-developed coating 16 in contact with the side of theformat sheet 11 having the photographically-developed coating 16thereon. Since the overlays are attached with their emulsion, or coatingside facing the format, the resulting composite is positively readablefrom the side of the format to which the overlays are attached. Inphoto-mechanically producing prints from this composite, the compositeis positioned with the back, or uncoated, side of the format sheet incontact with the emulsion side of the autopositive paper on which thefinal print is to be made.

The paper is then exposed and suitably developed, as

previously described. 7

Most advantageous is the fact that, in our composite, thephotographically-developed coating of each overlay is in substantiallythe same plane as the photographicallydeveloped coating of the formatsheet, as can be seen in Fig. 6. Hence, during the contact-typephoto-mechanical reproduction process described above, all of the imageson the composite film are at substantially the same distance from thesurface on which the final print is to be made. This assures that theimage lines on the final print will be of consistent density andsharpness. The

fact that the images on both the overlays and the format sheet areexposed through only a single thickness of film also contributes to thesharpness and density of the lines on the print.

The fact that our method utilizes positive film overlays containingprinted matter of such a nature that it is reversely-readable from theemulsion, or coating, side of the overlays has still another importantadvantage.

In addition to lending themselves to high quality prints in the mannerdescribed above, these overlays also lend themselves, in a highlyadvantageous manner, to a rapid and simple one-step method ofpreparation. More particularly, we prepare the overlays from a drawing,prefj erably inked, by superimposing a sheet of clear autopositive filmon the drawing with its emulsion, or coated,

side in contact with the inked side of the drawing. The auto-positivefilm is then suitably exposed, as in a vacuurn-frame, and after beingdeveloped contains on its emulsion side a reverse-reading image of thedrawing,

- as is desired for the method of our invention. Thus, the

need for intermediate negatives and the steps required to produce suchnegatives is completely obviated.

Af ter the required number of prints have been made from theabove-described composite, it is a simple matter to disassemble thecomposite and then to file the overlays away for subsequent reuse. Toaid in such disassembly, the plastic tape is selected to be of a typewhich is readily detachable from the surfaces of the film.

To facilitate ordering, filing, and actual use of the various componentsof our invention, it is desirable that they each be assigned some formof easily distinguishable identification. It has been found that themost practical manner of identifying the components is to apply writtenor printed identification marks to each component. The,

one problem presented by this manner of identification isthatwrittenidentification marks applied to the overlaysand the format normally willtend to appear on the final print, along with the other written materialon the overlays and format. For obvious reasons, this is generallyundesirable.

In those prior methods where negatives, instead of positives, were used,this problem could be easily over-,

come by applying the identification marks to an opaque portion of thenegative. With positives, however, there is rarelyan opaque area largeenough to accommodate an easily-distinguishable identification mark. Wehave v l overcome this problem, as it exists with positive films, byapplying the'identification marks to the film with a translucent dye ofacolor which is visibleto-the naked eye but is transparent to, ortransmits, thelight which. is used in the *finalphotomechanical printingprocess. For: example the color of the translucent dye can be ofapproximately the same color as" the. color offthellight used inthe.finallprintingprocess. In this regard, ,we have found that atranslucent yellow dye fsuitably applied to they positivefilm usedcombination with a yellow exposure light pioduces excellent results. Inthe final printing process fthe marked region oflthe film be'haves as ifthere. were no "identification thereon as a result, hese markings do notappear orftlie final print.

Although we have shown only one location index sheet and one formatsheet, it is to be understood that any number of these in widely orslightly differing form can be available for use with the overlaysshown, as well as with additional overlays not shown, thus providing fora virtually infinite number of possible combinations. In these caseswhere more than one format sheet-or location index sheet is available,the coded instruction sheet should, of course, specify, as by referenceto their above-described identification marks, which ones of thesesheets are to be used for the particular drawing that is being prepared.It is also to be understood that the term, transparent, as usedthroughout this specification to describe the format sheet and theoverlays, is intended to comprehend various degrees of translucency. Itis to be further understood that the term print, as applied to the finalproduct, is used in its broad sense and is intended to apply not only tofinal working drawings or copies but also to easily-reproducible typedrawings which can, in turn, be relied upon for such final drawings.

While we have shown and described a particular embodiment of ourinvention, it will be obvious to those skilled in the art that variouschanges and modifications may be fnade without departing from ourinvention in its broader aspects and we, therefore, intend in theappended claims to cover all such changes and modifications as fallwithin the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A method of making technical drawings comprising the following steps:providing a plurality of transparent format sheets having identifyingmarks thereon and having basic illustrative matter printed thereon,providing location index sheets having identifying marks thereon andhaving certain areas thereof delineated and positionally coordinatedwith the printed matteron said format sheets, providing a plurality oftransparent overlays which contain additional printed matter depictingcomponents which it is desired to have appear in the final form of saidtechnical drawings and which are adapted to fit over said delineatedareas and which are identified with distinctive markings, then preparinga coded instruction form in which distinctive markings of preselectedoverlays are assigned to preselected areas on said location index sheet,and in which the identifying mark on a preselected format sheet isassigned to the identifying mark on a preselected location index sheet,superimposing said preselected transparent format sheet upon said preselected location index sheet in a preselected position thereon whereinpreselected indicia on said two sheets register thus rendering thedelineated areas of said location index sheet visible through saidformat sheet, removably attaching those overlays designated by saidinstruction form to the format sheet in locations registering with thosedelineated areas of the location index sheet specified by saidinstruction form using the location index sheet as a guide for preciselocation of the overlays, said attaching step being so performed thatsaid overlays remain attached to said format sheet if said format sheetis su sequ nt y enov dfrbm said. lcca i u index he t.

then removing from the location index sheetthe ,corn

posite comprising the'format sheet an the attached overv a M e r q a aposit v P nt m said a no y, a p om h ical Pr nt g process, which comillustrative matter in a form-that; is: positively readablev from saidcoating side, said oyerlaysl each comprisingl'a lex b sh ofinosi x l ena ness as the format sheet and liavingon' one of its sides aphotographically-developed coating containing said additional printedmatter in a form that is reversely readable from the coating side ofsaid overlay, said overlays being attached to said format sheet withtheir respective coatings in contact with the coating side of saidformat sheet and with their opposite sides bare.

2. The method of claim 1 wherein said overlays are produced by aprinting process which comprises positioning the emulsion side of atransparent sheet of autopositive film in contact with positive-readingillustrative material provided on a sheet of drawing, and thereafterexposing the autopositive fihn to provide on its emulsion side areverse-readingimage of said illustrative material.

3. The method of claim 1 in which the attached overlays areattached tosaid format sheet by applying transparent pressure sensitive tape to theoverlays and the format sheet.

4. A method of making technical drawings comprising the following steps:providing a plurality of transparent format sheets having identifyingmarks thereon and having basic illustrative matter printed thereon,providing a plurality of location index sheets having identifying marksthereon and having certain areas thereof delineated and positionallycoordinated with the printed matter on said format sheets, providing aplurality of transparent overlays which contain additional printedmatter depicting components which it is desired to have appear in thefinal form of said technical drawings and'which are adapted to fit oversaid delineated areas and which are identified with distinctivemarkings, then preparing a coded instruction in which distinctivemarkings of preselected overlays are assigned to preselected areas onsaid location index sheet and in which the identifying mark on apreselected format sheet is assigned to the identifying mark on apreselected location index sheet, superimposing said preselectedtransparent format sheet upon said preselected location index sheet in apreselected position thereon wherein preselected indicia on said twosheets register thus rendering the delineated areas of said locationindex sheet visible through said format sheet, removably attaching thoseoverlays designated by said instruction form to the format sheet inlocations registering with those delineated areas of the location indexsheet specified by said instruction form using the location index sheetas a guide for precise location of the overlays, said attaching stepbeing so performed that said overlays remain attached to said formatsheet if said format sheet is later removed from said location indexsheet, then removing from the. location index sheet the compositecomprising the format sheet and the attached overlays, and thenproducing a positive print from said composite by a photo-mechanicalprinting process which comprises exposing a sheet of autopositivematerial while said sheet of material is disposed in contact with saidcomposite, said format sheet being a flexible sheet of positive filmhaving on one of its sides a photographicallydeveloped coatingcontaining said basic printed matter in a form that is positivelyreadable from the overlay receiving side of said format sheet, each ofsaid overlays comprising a flexible sheet of positive film of generallyhe, e a J the same thickness as the format sheet and having on one ofits sides a photographically-developed coating containing saidadditional printed matter in a form that is r'eversely readable from thecoating side of said overlay, said overlays being attached to saidformat sheet with their respective coatings in contact with said formatsheet and with the respective opposite sides of said overlays bare, saidphoto-mechanical printing process comprising exposing said sheet ofauto-positive material with said composite in contact therewith to anexposure light of a predetermined color capable of exposing saidautopositive material, said identifying markings for said overlays beingapplied to the overlays with a'translucent dye of substantially saidcolor which is visible/to the naked eye but transparent to said exposurelight, whereby said markings do no appear on the final print. I

References Cited in the file of this'patent UNITED STATES PATENTS.

182,624 Alissoif Sept 26;

980,290 Kubel ,et a1. -.Ian;3," 1911 1,736,445 'Janenga et al Nov; 19',1929 1,777,144 Innes Sept. 30, '1930 1,896,739 Breslauer Feb. 7, 19332,200,203 Heintz Feb. 7,1940 2,369,449 Fallesen Feb. 13, 1945 2,752,245Hough et al.' June 26, 1956

1. A METHOD OF MAKING TECHNICAL DRAWINGS COMPRISING THE FOLLOWING STEPS:PROVIDING A PLURALITY OF TRANSPARENT FORMAT SHEETS HAVING IDENTIFYINGMARKS THEREON AND HAVING BASIC ILLUSTRATIVE MATTER PRINTED THEREON,PROVIDING LOCATION INDEX SHEETS HAVING IDENTIFYING MARKS THEREON ANDHAVING CERTAIN AREAS THEREOF DELINEATED AND POSITIONALLY COORDINATEDWITH THE PRINTED MATTER ON SAID FORMAT SHEETS, PROVIDING A PLURALITY OFTRANSPARENT OVERLAYS WHICH CONTAIN ADDITIONAL PRINTED MATTER DEPICTINGCOMPONENTS WHICH IT IS DESIRED TO HAVE APPEAR IN THE FINAL FORM OF SAIDTECHNICAL DRAWINGS AND WHICH ARE IDENTIFIED WITH OVER SAID DELINEATEDAREAS AND WHICH ARE IDENTIFIED WITH DISTINCTIVE MARKINGS, THEN PREPARINGA CODED INSTRUCTION FORM IN WHICH DISTINCTIVE MARKINGS OF PRESELECTEDOVERLAYS ARE ASSIGNED TO PRESELECTED AREAS ON SAID LOCATION INDEX SHEET,AND IN WHICH THE IDENTIFYING MARK ON A PRESELECTED FORMAT SHEET ISASSIGNED TO THE IDENTIFYING MARK ON A PRESELECTED LOCATION INDEX SHEET,SUPERIMPOSING SAID PRESELECTED TRANSPARENT FORMAT SHEET UPON SAIDPRESELECTED LOCATION INDEX SHEET IN A PRESELECTED POSITION THEREONWHEREIN PRESELECTED INDICIA ON SAID TWO SHEETS REGISTER THUS RENDERINGTHE DELINEATED AREAS OF SAID LOCATION INDEX SHEET VISIBLE THROUGH SAIDFORMAT SHEET, REMOVABLY ATTACHING THOSE OVERLAYS DESIGNATED BY SAIDINSTRUCTION FORM TO THE FORMAT SHEET IN LOCATIONS REGISTERING WITH THOSEDELINEATED AREAS OF THE LOCATION INDEX SHEET